Mitosis- lecture #13 Flashcards
what is the function of cell division?
to divide one parent cell into two identical daughter cells
what is mitosis important for?
tissue repaire
what type of cell does mitosis occur in?
eukaryotes
is cell division accurate?
highly accurate and highly complex process
what happens when HIV replicates?
trainwreck
it brings its own enzyme and therefore is not accurate at replicating
HIV changes so much because the virus isnt the same from 1 day to the next
what is used instead of mitosis in prokaryotes?
binary fission
what is a genome?
total cellular DNA content
what is a plasmid?
contains non-essential genes
small circular piece of DNA
(in addition to the bacterial chromosome)
what is the formation of DNA in eukaryotes?
many linear DNA molecules
how long is the genomic DNA in humans?
2 meters organized into chromosomes (250, 000x cell diameter)
how many chromosomes do humans have? how many chromosomes do dogs have?
humans: 46
dogs: 78
dogs have more because they’re given more from mom and dad
why do dogs have more chromosomes then humans?
the increase in chromosomes doesn’t complicate the complexity of a chromosome
what do eukaryotes have to be able to do to replicate this DNA?
must be able to replicate DNA
must be able to separate into 2 equal daughter cells
what are chromosomes?
DNA and proteins in a complex called a chromosome
what do proteins do on chromosomes?
allow the maintenance of cell structure
assist with DNA function
keeps the DNA structure highly ordered
what does DNA consist of?
100s-1000s of genes
what do genes do?
specify an individuals traits
what is chromatin?
DNA + protein = chromatin
varied degrees of condensation
what are the 2 categories of human cells?
somatic cells
gametes
what are somatic cells?
body cells
how many chromosomes are in a somatic cell? where are they located?
46 chromosomes
located in the nucleus
how many pairs of somatic cells do humans have? where are they from?
23 pairs
one version from mom and one version from dad
what are gametes?
sex cells (used for reproduction)
how many chromosomes do gametes have?
23 chromosomes
what happens to the number of chromosomes of gametes after fertilization?
double (diploid)
46 chromosomes
chromosomes are long and thin when not actively undergoing division, what is this called?
chromatin
what does chromatin do in preparation for cell division?
froms a densely coiled, folded structure
its shorter and easily visible with a microscope
why does chromatin duplicate?
in order to provide enough DNA for 2 cells following division
what is the next step after duplication?
the photocopy of the original is joined together with the original
what are the photocopy and original joined together called?
sister chromatids
what are sister chromatids attached by?
centromere
during cell division what happens to sister chromatids?
they seperate
when sister chromatids are separated but still apart of the same cell what are they called?
chromatids
when the cell completely divides what are the chromatids called?
chromosomes
each cell that results from the division will be identical to what?
the parent cell
what is mitosis used for?
produce new cells
replace damaged cells
what are the 2 phases of mitosis?
division of genetic material
division of cytoplasmic contents
what is meiosis used for?
produce gametes (sperm and egg)
what kind of cells does meiosis create?
non-identical cells
(contributes to genetic variation)
how many haploid chromosomes are produced in meiosis?
23 haploid
where does meiosis occur?
gonads (testes and ovaries)
what restores the diploid number of chromosomes in meiosis?
fertilization
sperm (23) + egg (23) = 46
what are the 2 main phases of mitosis?
interphase and mitosis
what is interphase?
before cell division therefore does not involve cell division
how much % does interphase account for in the cell cycle?
90%
what is the purpose of interphase?
duplication of chromosomes
increases in cell size and number of organelles
what are the 3 phases in interphase?
G1, S, G2
what does G1 do and how long is that process?
4-6 hours
makes organelles and enzymes, the cell grows